Container



Dec. 28, 1954 5. VIZCARRONDO ET AL CONTAINER Filed June 18, 1953 4 Sheets-Shee- INVENTORS. 1552/ V/ZCAEEO/VDO JCLSEW/ qm/wv 2,455

Dec. 28, 1954 G. VIZCARRONDO ETAI. 2,593,125

CONTAINER 4 Sheets-Sheet 2 Filed June 18, 1953 INVENTORS. G/LEEU v/zcA/eeoA/oo JOSEPH GLEN/V e455 Dec. 28, 1954 e. VIZCARRONDO ETAL 2,698,125

CONTAINER Filed June 18, 1955 4 Sheets-Sheet 25 46 INI 'ENTORS.

45527 V/ZCAEEOA/DO f05E/ /1 Gif/V/V 015m BY QMMW A TTOZA/EXS Dec. 28, I954 e. VIIZCARRONDO ETAL 2,698,125

CONTAINER 4 Sheets-Sheet 4 Filed June 18, 1953 Ti .15. 15' INVENTOR.

47745527 wzoueeomaa JOSEPH 545W 6455) United States Patent CONTAINER Gilbert Vizcarrondo and Joseph Glenn Rabby, Jacksonville, Fla., assignors to National Container Corporation, New York, N. Y., a corporation of Delaware Application June 18, 1953, Serial No. 362,572

15 Claims. (Cl. 22927) The present invention relates to the structure of a container particularly designed for facilitating the transportation of fresh vegetables, but also useable for other purposes where strength, rigidity of shape, and economy are important factors.

The present invention is specifically directed to the production of a compartmented or partitioned container, preferably including cover flaps to close the open top thereof, all made from a single blank appropriately cut and scored to facilitate erection of the box. The various container walls, usually of multi-ply construction for added strength, are so structurally interrelated and interlocked that any tendency of the walls to bulge is effectively resisted. The cover panels are adapted to engage, either frictionally or positively, with handles provided on the partition panels and extending up therefrom, the cover panels thus reliably being retained in folded down condition after the box has been filled. When the containers are made from blanks of corrugated paperboard, the design is such that the corrugations are vertical in all of the vertically extending plies, thus making for maximum strength when the boxes are stacked one above the other. In one embodiment here illustrated provision is made for upward bulging of the cover panels to take into account the situation where the initial packing of the container results in some of the contents thereof extending above the top edges of the side or end Walls thereof. During shipping and handling of the package the contents have a tendency to settle, and the disclosed construction permits the cover panel to conform thereto. This latter embodiment is formed from a blank considerably closer to a rectangular shape than that involved in the production of the first disclosed embodiment, thus leading to a more economical use of the board. However, the first disclosed embodiment provides for somewhat greater security in retaining the cover panels in their folded down position.

To the accomplishment of the above, and to such other objects as may hereinafter appear, the present invention relates to a container structure as defined in the appended claims and as described in this specification, taken together with the accompanying drawings, in which:

Fig. 1 is a top plan view of the blank employed to produce one embodiment of the present invention;

Fig. 2 is a three-quarter perspective view showing a container made from the blank of Fig. 1 in an intermediate stage of erection;

Fig. 3 is a view showing said container in a later intermediate stage of erection;

Fig. 4 is a similar view showing said container fully erected but with the cover panels open;

Fig. 5 is a similar view but showing said container with the cover panels folded down to closed condition;

Fig. 6 is a cross sectional View taken along the line 6-6 of Fig. 4;

Fig. 7 is a cross sectional view taken along the line 7--7 of Fig. 5

Fig. 8 is a cross sectional view taken along the line 8-8 of Fig. 4;

Fig. 9 is a top plan view of the blank from which a second embodiment of the present invention is made;

Fig. 10 is a three-quarter perspective view showing a container made from the blank of Fig. 9 in an intermediate stage of erection;

Fig. 11 is a similar view showing said container in a later intermediate stage of erection;

2,698,125 Patented Dec. 28, 1954 Fig. 12 is a similar view of said container in a still later intermediate stage of erection;

Fig. 13 is a similar view showing said container fully erected and with its cover flaps folded down to closed position;

Fig. 14 is a cross sectional View taken along the line 1414 of Fig. 12; and

Fig. 15 is a cross sectional view taken along the line 15-15 of Fig. 13.

Having reference first to the embodiment of Figs. l-8, the blank comprises a bottom wall panel 2 with side wall panels 4 and 6 secured thereto along foldlines 8 and 10 respectively. An end wall panel 12 is secured to the right hand edge of the side wall panel 4 via foldline 14, the right hand edge of the end wall panel 12 having a flap 16 foldably secured thereto along foldline 18. End wall reinforcing panel 20 is secured to the upper edge of the end wall panel 12 by means of the separated foldlines 22, a slot 24 being provided as shown. A bottom Wall reinforcing panel 26 is secured to the lower edge of the end wall panel 12 via foldline 28, the panel 26 being separated from the bottom wall panel 2 by means of cut 30. A partition panel 32 is secured to the lower edge of the bottom wall reinforcing panel 26 via foldline 34 and has a handle 36 extending thereabove, said handle having an aperture 38 therethrough. A flap 40 is secured to the right hand edge of the partition panel 32 via foldline 42, cut 30 separating the partition panel 32 from the bottom wall panel 2 and side wall panel 6. A similar but oppositely oriented arrangement of end wall panel 12', end wall reinforcing panel 20, bottom wall reinforcing panel 26 and partition panel 32, together with flaps 40 and 16 and appropriate foldlines and cuts, is foldably secured to the left hand edge of the side wall panel 6 by means of foldline 14'.

Cover panel 46 is secured to the right hand end of the upper edge of the side Wall panel 4 by foldline 44, that panel 46 having a tab 48 extending laterally out therefrom, secured thereto along foldline 50 and separated from the end wall reinforcing panel 26 by means of cut 52. Extending to the other side of the cover panel 46 and preferably substantially rigid therewith is a hooked portion 54 defining the slot 56 between itself and the end of the cover panel 46. Secured to the left hand end of the upper edge of the side wall panel 4, via double foldlines 58, is side wall reinforcing panel 60 separated from the cover panel 46 by cut 62 and having flap 64 secured to the outer end thereof by means of foldline 66. A similar but oppositely oriented arrangement, including cover panel 46 and side Wall reinforcing panel 60', is provided at the lower end of the blank of Fig.

1, secured to the side wall panel 6, the cover panel 46' being opposite the side wall reinforcing panel 60 and the side wall reinforcing panel 60 being opposite the cover panel 46.

For ventilation purposes the side wall panels 4 and 6 are provided with apertures 68, the lower end of the side wall reinforcing panels 60 and 60' having slots 70, 70 respectively which register with the apertures 68 when the container is erected. The cover panels 46 and 46 may be provided with apertures 73 and 73' respectively, which assist in ventilation and which also function as6 finger holes to facilitate manipulation of the panels 4 46'.

The first step in the erection of the container, as shown in Fig. 2, is to fold up the side Wall panel 4 and fold the end wall panel 12 at right angles thereto so as to close one end of the container, the bottom wall reinforcing panel 26 having previously been folded at right angles to the side wall panel 12 so as to rest upon a portion of the bottom wall panel 2. The partition panel 32 is bent up vertically and the flaps 16 and 40 are bent inwardly, all as shown in Fig. 2. The bottom wall reinforcing panel 26 preferably has the same width as the bottom wall panel 2, but only half the length, so that the partition panel 32 is positioned midway of the length of the bottom wall panel 2.

The next step, as shown in Fig. 3, is to perform substantially the same operation with the end wall panel 12', bottom wall reinforcing panel 26' and partition panel 32",

the two partition panels 32 and 32 thus being disposed back to back midway of the container, their handles 36, 36' extending up alongside one another with the apertures 38, 38 in registration. The flaps 16 and 40 extend along the right hand end of the side wall panel 6 and when the side wall reinforcing panel 60 is folded down, as shown in Fig. 3, it grasps the flaps 16 and 40 between itself and the side wall panel 6. The fiap 64 on the side wall reinforcing panel 60 is bent at right angles thereto so as to extend along the inner surface of the end wall panel 12. When the end wall reinforcing panel 20 is bent down, it grasps the flap 64 between itself and the end wall panel 12, as shown in Figs. 4 and 6. A comparable series of operations are performed on the left hand side of the container.

As a result a container is formed having a double ply bottom wall defined by the bottom wall panel 2 and the bottom wall reinforcing panels 26 and 26', a double ply central partition defined by the two partition panels 32 and 32, a double ply end wall at each end defined by the panels 12, 20 and 12, 20 respectively, and side walls half of the length of each of which are of double ply construction, defined by half the panel 4 and the panel 60 and by half the panel 6 and the panel 60 respectively. it will be noted that if corrugated board be employed to form the container of the instant invention, and if the corrugations should run in the direction of the arrow 71 of Fig. 1, then all of the vertical walls and the plies and flaps which make them up will have their corrugations running vertically, thus providing for maximum strength when the containers are stacked.

The cover panels 46 and 46' are foldably secured to the upper edges of the one-ply portions of the side walls and are adapted to be folded down to close the open top of the container after the container has been filled. In order to retain the cover panels 46 and 46' in their downwardly folded position, the slots 56 defined by their laterally extending hooked portions 54 are so positioned as to snugly frictionally receive therein the handles 36, 36' on the partition panels 32, 32' respectively. The periphery of the handles 36, 36 is so shaped as to permit the hooked portions 54, 54 to pass therearound only upon the application of appreciable force, thus assisting the frictional fit of the handles 36, 36 widthwise of the slots 56, 56 in retaining the cover panels 46, 46 in downwardly folded position. In addition, the tabs 48, 48' are adapted to be received through the slots 24, 24 respectively, thus further frictionally retaining the cover panels in closed position. It will be noted that the slots 24, 24 are positioned inwardly of the ends of the flaps 64', 64 respectively so that those flaps do not interfere with the reception of the tabs 48, 48' between the end wall panels 12 or 12 and the end wall reinforcing panels 20 or 20' via the apertures 24 or 24.

The flaps 64 and 64, received as they are between the end wall panels 12, 20 and 12, 20 respectively, prevent the end walls from bulging outwardly by locking their free edges in position. The flaps 16 and received between the side wall panels 6 and and the flaps 16 and 40' received between the side wall panels 4 and 60 respectively, serve to keep the side walls from bulging outwardly by locking their free edges in position. The interengagement of the hooked portions 54, 54 around the handles 36, 36' serve to retain the handles and partitions 32, 32' in properly oriented position, and also positively prevent outward bulging of those single-ply portions of the side walls 4 and 6 respectively to which they are attached. The tabs 48, 48, as they pass through the apertures 24, 24' respectively, further assist in this reinforcing action. They also lock the end walls inposition and prevent them from bulging. The frictional fit of the flaps 16 and 16 between the panel pairs 6, 60 and 4, 60 respectively assist in this function.

The handles 36, 36 may be folded down over the closed cover panels 46, 46 so as to permit the containers to be stacked one upon the other.

The embodiment of Figs. 9-15 is formed from a blank shown in Fig. 9. It will be noted that said blank, when compared with the blank of Fig. l, is much more closely rectangular and consequently can be produced with considerably less wastage of material.

This second container embodiment comprises a bottom wall panel 72 to which side wall panels 74 and 76- are connected by means of foldlines 78 and 80 respectively. An end-wall panel 82 is connected to the right hand edge of the side wall panel 74 via folding 84, the right hand edge of the panel 82 having an elongated flap 86 foldably secured thereto along foldline 88. A bottom well reinforcing panel 90 is connected to the lower edge of the end wall panel 82 by foldline 92, and partition panel 94 is connected to the lower edge of the bottom wall reinforcing panel 90 by means of toldline 96, the bottom wall reinforcing panel 90 and the partition panel 94 being separated from the bottom wall 72 and the side wall panel '76 by means of cut 98. A handle extends from the partition panel 94, that handle having an aperture 102 therethrough and having a flap 104 formed therein and, when bent out from the plane of the handle 10f), partially defining the aperture 102. A flap 106 is secured to the right hand edge of the partition panel 94 by means of foldline 108. The combined lengths of the flaps 86 and 106 are preferably substantially equal to one-half the length of the bottom wall panel 72 and the side wall panels 74 and 76. Attached to the upper edge of the end wall panel 82 by foldline 110 isa cover panel 112 having a foldline 114 extending laterally thereacross intermediate its length and having a tab 116 of reduced width projecting therefrom, the width of the tab 116 being comparable to the width of the aperture 102 formed in the handle 100. A similar but oppositely oriented arrangement of end wall panel 82, bottom wall reinforcing panel 90", partition panel 90, partition panel 94 and cover panel 112, and appropriate foldlines and cuts, is secured to the left hand edge of the side wall panel 76 by means of foldline 84. The handle 100 has an aperture 102 but does not have a flap 104.

As in the previous embodiment, it is preferred that the length of the bottom wall reinforcing panels 90 and 90 equal the length of the bottom wall panel 72, so that the partition panels 94, 94 will be positioned back to back, thus defining a two-ply partition.

Side wall reinforcing panel 120 is secured to the right hand end of the upper edge of the side wall panel 74 by double foldlines 118. Secured to the left hand end of the upper edge of the side wall panel 74, via double foldlines 122, is another side wall reinforcing panel 124 spaced from the panel 120 by means of cut 126, and an end wall reinforcing panel 128 is connected to the left hand edge of the panel 124 by means of foldline 130, the end wall reinforcing panel 128 being cut out at 132 in order to define the handle 100'. The side wall reinforcing panel 120 is separated from the cover panel 112 by means of vcut 134. A similar but oppositely oriented arrangement is provided at the lower end of the blank of Fig. 9, secured to the side wall panel 76, the side wall reinforcingpanel 120 being opposite the panel 124 and the side wall reinforcing panel 124' being opposite the panel 120.

Erection of 'a container from the blank of 'Fig. 9 proceeds to a large extent similarly to that of the previous embodiment, as may be seen from an examination of Figs. 1013. First the side wall panel 74 is bent up, the end wall panel 82 is bent into position, the bottom wall reinforcing panel 90 rests on top of the bottom wall panel'72, the partition panel 94 is bent upright, and the flaps 36 and 106 are bent toward one another, all as shown in. Fig. 10. Then the same procedure is carried out at the other end of the container, giving rise to the structure shown in Fig. 11. Thereafter, the side Wall reinforcing panels124 and 124 are bent down inside the container, the end wall reinforcing panels 128 and 128 being bent at right angles thereto so as to lie along the inner surfaces of the end Wall panels 82 and 82. The panels 124 and124', together with those portions of the side walls '74 and';76 to which they are connected, encompass the'fiaps 86, 106' and 86 andil06 respectively. Next the side wall reinforcing panels 120 and 120' are folded down, engaging the free ends of the end wall reinforcing panels 128 and 128 so as to hold the latter inv position. The frictional interengagement is quite tight, so that all of .the panels are retained in assembled condition. The flap 104on the handle 100 may bebent' through the aperture 102' in the handle 100' and then up around the handle 100', so as to tend to hold the handles, and hence the partition panels 94and 94, against one another.

In the box structure as thus far described, it will be noted that if the corrugations in the blank of Fig. 9 are running in the direction of the arrow 136, those corrugatIOIISWiH be running vertically in all ofthe vertically directed panels 94, 94,74,'76, 120,..120',-124, 124', 128,

128', 82 and 82, as well as in the flaps 86, 86', 106, 1Q6'. Thus maximum strength in a vertical direction will be produced. All of the walls, bottom, side, top and end, are of at least two-ply construction, non-registering halves of each of the side walls being of three-ply constructions.

The cover panels 112 and 112' are foldable down to cover the open top of the container after the container has been filled, the tabs 116 and 116 thereon being received within the apertures 102, 102 in the handles 100, 100 so as to serve to retain the cover in closed position, although not with as much security as in the previously described embodiment. However, the cover of the instant embodiment has a unique feature of considerable importance, particularly insofar as the packaging of fruit and vegetables are concerned. Because each of the cover panels 112, 112' has a foldline 114 extending laterally thereacross, and because the tabs 116, 116' are slidable longitudinally through the handle apertures 102, 102', the cover panels may be closed even though the contents of the container may extend higher than the upper edges of the side and end walls, the appropriate cover panels 112, 112 bulging upwardly along the foldlines 114, 114' to accommodate therefor, as shown in Figs. 13 and 15. It usually is the case that after the filled container has been handled, the contents thereof tend to settle, and the cover panels 112, 112 will conform thereto, the tabs 116, 116' sliding more fully into the apertures 102, 102'. As in the previous embodiment, the handles 100, 100 can be folded down parallel to the cover panels 112, 112' when the boxes are to be stacked one above the other.

The embodiment of Figs. 915, like the previous embodiment, represents a one-piece partitioned container having unusual strength, multi-ply walls, having vertical walls the corrugations of which all run vertically, and interengaging walls which reliably prevent bulging of the container. In addition, cover panels of novel design are incorporated into this embodiment, which cover panels can be closed even when a heaping load is placed within the container, the cover panels being retained in closed condition in such a wall that they can accommodate the selves to settling of the container contents.

While but two embodiments of the present invention have been here disclosed, it will be apparent that many variations may be made in the details thereof without departing from the spirit of the invention as defined in the following claims.

We claim:

1. A substantially rectangular blank for forming a partitioned container, said blank comprising a bottom panel, a pair of side wall panels each connected to said bottom panel by a foldline and extending therefrom toward opposite sides of the blank, a pair of end wall panels, each secured to only one side wall panel at one end thereof by a foldline and each secured to a different side wall panel and extending therefrom toward opposite ends of the blank, bottom reinforcing panels secured to said end wall panels respectively by foldlines and extending therefrom toward opposite sides of the blank, said bottom reinforcing panels being adapted to overlie portions of said bottom panel when said container is erected, and partition panels secured to said bottom reinforcing panels by foldlines and extending therefrom toward opposite sides of the blank, said partition panels being adapted to be bent up therefrom between and substantially perpendicular to said side wall panels when said container is erected.

2. The blank of claim 1, said end wall panels and said partition panels having flaps secured thereto by foldlines and adapted to be bent toward one another adjacent one side wall when said container is erected, said side wall panel having a side wall reinforcing panel secured thereto by a foldline and adapted to be bent down parallel to said side wall and around said flaps when said container is erected.

3. The blank of claim 2, said side wall reinforcing panel having a flap secured thereto by a foldline and adapted to be bent along said end wall panel when said container is erected, said end wall panel having an end wall reinforcing panel secured thereto by a foldline and adapted to be bent down parallel to said end wall panel and around said fiap on said side wall reinforcing panel when said container is erected.

4. The blank of claim 1, each of said end wall panels and said partition panels having flaps secured thereto by foldlines and adapted to be bent toward one another adjacent one side wall panel when said container is erected, said flaps together having a combined height and width substantially equal to the height and width of that part of said side wall panel between said partition panel and said end wall panel, said side wall panel having a side Wall reinforcing panel secured thereto by a foldline and adapted to be bent down parallel to said side wall panel and around said flaps when said container is erected.

5. The blank of claim 4, said side wall reinforcing panel having a flap of substantially the same length and width as said end wall panel secured thereto by a foldline and adapted to be bent along said end wall panel when said container is erected.

6. The blank of claim 4, said side wall reinforcing panel having a flap of substantially the same length and width as said end wall panel secured thereto by a foldline and bent along said end wall panel when said container is erected, the opposite side wall panel having a reinforcing flap secured thereto by a foldline, said flap having a length substantially equal to the distance between said partition panel and said side wall reinforcing panel flap and adapted to be bent down inside said opposite side wall panel so as to engage the facing surfaces of said partition panel and said side wall reinforcing panel flap and hold the latter in place when said container is erected.

7. The blank of claim 4, said side wall reinforcing panel having a flap of substantially the same length and width as said end wall panel secured thereto by a foldline and adapted to be bent along said end wall when said container is erected, the opposite side wall panel having a reinforcing flap secured thereto by a foldline, said flap having a length substantially equal to the height of said opposite side wall panel and adapted to be bent down inside said opposite side wall panel so as to engage the upper surface of said bottom wall reinforcing panel and the facing surfaces of said partition panel and said side wall reinforcing panel flap and hold the latter in place when said container is erected.

8. In the blank of claim 4, a handle panel on at least one of said partition panels and adapted to extend from said partition panel above said side and end wall panels when said container is erected, said side wall reinforcing panel having a flap of substantially the same length and width as said end wall panel secured thereto by a foldline and adapted to be bent along said end wall panel when said container is erected, the opposite side wall panel having a reinforcing flap secured thereto by a foldline, said flap having a length substantially equal to the distance between said partition panel and said side wall reinforcing panel flap and adapted to be bent down inside said opposite side wall panel when said container is erected so as to engage the facing surfaces of said partition panel and said side wall reinforcing panel flap and hold the latter in place, and a cover panel secured to said end wall by a foldline and of a size to substantially completely cover that part of the open top of said erected container between said end wall panel and one of said partition panels, said cover panel having a laterally extending foldline intermediate its length and a tab of appreciable length extending longitudinally therefrom, said handle having an aperture in line with said tab through which said tab is passable when said container is erected and said cover panel is folded down, engagement between said tab and said aperture serving to retain said cover panel in folded down position and said tab being slidable through said aperture so as to permit said cover panel to bulge upwardly by bending about its laterally extending foldline.

9. The blank of claim 1, in which said bottom reinforcing panels have a combined length substantially equal to the length of said bottom panel.

10. In the blank of claim 9, a handle secured to at least one of said partition panels, a cover panel secured to one of said wall panels, and an element extending from said cover panel and adapted to engage with said handle when said container is erected and said cover panel is in folded down position so as to retain it in that position.

11. In the blank of claim 1, a handle secured to at 1east one of said partition panels, a cover panel secured to one of said wall panels, and an element extending from said cover panel and adapted to engage with said handle when said container is erected and said cover panel :is in folded down position so as to retain it in that position.

2- In the ank t c m 1. n apert e andle .39- cured to at least one of said partitionpanels, a cover -panel secured to one of said wall, panels and having a laterally extending foldline intermediate its'length and a is folded down, said tab having a width less than that ,of

said pert e e a ar a,me kn sre r length than the thickness of said handle, engagement between said taband said aperture serving to retain said cover panel in folded down" position andsaid tab" b.eing freely slidable through said aperture so as to perm t said cover panel to bulge upwardly by bending about its laterally extending foldline.

13. A partitioned container comprising a bottom wall, a pair of side walls foldably securedthereto, end walls each foldably secured to a different one of said side walls, bottom wall reinforcing panels foldably secured to said end walls and overlying portions of said bottom wall, said bottom wall reinforcing panels having a combined length substantially equal to the length of said bottom wall, partition panels foldably secured to said bottom wall reinforcing panels respectively and bent. up therefrom adjacent one another between and substantially perpendicular to said side walls, each of said end walls and said partitions having flaps foldably secured theretoand .bent toward one another adjacent one side Wall, said flaps together having a combined height and width substantially equal to the height and width tothat part of said side wall between said partition and said .end wall, said side wall having a side wall reinforcing panel foldably secured thereto and bent down parallel to said sidewall and around said flaps, said .side wall reinforcing panelhaving a flap of substantially the same length and width as said end Wall foldably secured thereto 'and bent along said end wall, the opposite side wall having a reinforcing flap foldably secured thereto, said flap having a length substantially equal to the distance between said partitionand said side wall reinforcing panel flap and being bent down inside said opposite side wall so as to engage thefacing surfaces of said partition and .said side wall reinforcing vpanel flap and hold the latter in place.

14. The partitioned container of claim 13, in which the reinforcingfiap secured ito said opposite side wallhas alen th ubs an al equ o the e o sa opp side wall and is bentdown inside said opposite side wall so as toengage the upper surfaceofsaid bottom wall reinforcing panel and the facing surfaces of said partitionand said side wall reinforcing panel flap and holdingthelatter in p c 15. In the partitioned container of claim 13,, a handle on at least oneof said partition panelsandextending up therefrom above said side and end walls, and a cover panel foldably securedto said end wall and of asizeto substantially completely cover that part of the open top of said container between said end wall and one of said partition panels, saidcover panel having a laterally. ex.-

tending foldline intermediate its length and a tabof appreciable lengthextfinding longitudinally therefrom, said handle having an aperture in line with said tab through which saidtab is passablerwhen said cover panel is folded down, engagement between said tab and said aperture serving to retain said cover panel in folded downtposition and said tab being slidable through said aperture so as to permit said cover panel to bulge upwardly by bending about, its laterally extendingfoldline.

References Citedinthe file of thispatent UNITED STATES PATENTS Number Name Date 1,737,603 Maker Dec. 3, 1929 1,795,293 Boeye Mar. 10, 1931 1,973,035 Barron Sept. 11, 1934 1,977,102 Wheeler Oct. .16, 1934 1,987,063 Hinton Jan. 8, 1935 2,326,947 Hurreyet a1 Aug. 17, 1943 2,336,655 Tobey Dec. 14, 19.43 2,462,676 Riley etal. Feb. 22, 1949 2,468,951 Barter May 3, 1949 2,632,594 Nelson Mar. 24, 1953 2,647,679 Schilling et al Aug. 4, 1953 FOREIGN PATENTS Number Country Date 429,580 Great Britain Sept. 10,-1934 

